SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ef8fd620f8742de2382584232e6cd59d37be35221d2bea02f640294bf1b69b97' 
  AND token = 'E2R3hhZTN0VtQ/hhaD3rb7JF1NrhJEg8BsVYuXT5STU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}