SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25776766d0d9dcd222e2e23a4b86f0022b6f40e7a2e04f75b2cc5d2da4ed58b9' 
  AND token = 'nTvh1wnCojviSjU7SqBI3a3td8nXqhaPOIXOWDAnrMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}