SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5589e5dfe49e6764bea03dce665596c30c00b872530f3c673db8337b30e0800' 
  AND token = 'TM2Ob38dkkeY3CUxtHo3ZOMcYVhtd9XQ2B4/UoddTMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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