SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be54401f312ca1e868f99e1e04ae526a2bf207914f531d87c0887fe5f563d750' 
  AND token = 'G5xUv9RyqZfspc6yZ47XLIOyluMSdDhOleiOVNbqfPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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