SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17e14393fc2750ccc78ed0b692b362184f60738d3a590df80825d937477ecc3a' 
  AND token = 'wPHg9Db8pX2GcXcD7eVskSAX5n9tleVlSI74JfkMIoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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