SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3400475cbb7341c47ac320c598fe291082656a84302e4976b942501330ba3525' 
  AND token = '8OzHwL3iNVmA+atsIL7q83jZdG6iBe8rumHWc/L/oXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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