SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb915328ad1f59b796dc93a510b958ef8ad6e09cbc2281230c9402dbc6c77518' 
  AND token = 'as2UjvyOokZjx3JVy7nj2CCBmtsk56kONSJbnjgnMy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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