SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a264ba65d4f91074a59ceb0bcf1fbfd8c5874e904f26a946af1b45d3bc009264' 
  AND token = 'XZ5/YDYmAlqrfK6hK8lVrfEZ50j9QPNY/LcCxW7//mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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