SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ef79c0834337d4c642fb57b1a663b8fcb973855cede36c49722e76f577eb43a' 
  AND token = 'NUM4yDKAgRESXUbLQ6QRRcNaAq+p5WmM1lqzd1FLwYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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