SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a84dfd0b431368ab0d6e19920ec2467b312353d630a9a394a0dd07ef73a9a4a' 
  AND token = '4Ob4M64xpw0ziagMFH0VixL8Ifjn3BgP+/1wp5tB3NQ=' 
  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"
    }
  }
}