SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5e7301b7a54695bd746aa350b4e3a721efdb647140c378a67778ead35984265' 
  AND token = 'f0AcsTCdQgWTCYtJhIgsMN1o3xpBjPI0Z49erig6jtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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