SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6e4af966cbb1e54a52116447639901fb97dcbe29ba806fb9543625fd79fecccf' 
  AND token = 'yPgpFmnz/DBab6liooXxP3wFhmc7ruQC9wpZQtdB+9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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