SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0253e58406703feec4524bf0a642bf7b9a70ec27549c0e18990accf6e70661a' 
  AND token = 'FrPSEOUZbxFd6bIVLEX1Z3dSbgZ+O56RXDqX+gNQfbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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