SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bef29da9b6429c3989c230d539ac34428be930a686253a2504193b902cca554c' 
  AND token = 'I+yEDmgBXJWPIBfKMMQlskac4CBGkupuoCQNcL5pjzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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