SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54da18cdfc0608802cdc9f82141c673d96224685656755329586284c0ddf637e' 
  AND token = 'BzwLOnjFdH+6cfCPxe6eJIFbko9HNe9QVyLPSGtipbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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