SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a50aa2fde8e7493812b42999fe9862de8e13683bdab0c2dc757f90c805b73528' 
  AND token = 'A8Bx/ASFpHOClch1wGrwayBDNUB41BQEFuZgILeuOCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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