SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51a30f4e1a20cb66276177e4071da820b5b69c94dc4ec14184b109e84187ac33' 
  AND token = 'mtRqDr0iS1QeowlNyrKRkPoGdXEyIdSlM9lhSacsa6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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