SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f87be3329953db22bbd9cd02d9c64273b93d4890c52c62decd5c15d3c4caa640' 
  AND token = '5CPapdB2P1IZEeeit3THGyp0oQWyVVbwYfF4ga6kHQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}