SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '973a11376e832c3da4416b918f86cd06cb7685ad8e66225da27943cc5a21de3c' 
  AND token = 'FMvgGLMcbJnjUdtMczW9xVsHsSmqKG3vzhs0c1cDcpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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