SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5fc8a19e6f90babd899238566514619a3a7662829d1b242e20375d305bc32b3' 
  AND token = 'C7BqM+I3zSaIzsIpsd3gKiIkUMBdpqbY/8jSki2cfd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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