SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86e73486b1f7a607867d2e4f2091fdffc1a1fe82b08aec88d015bc8da7b0e992' 
  AND token = 'OB9qZS/Pr6AR9Jz+CBTXpge1mGAwRWIkOO3ZSVayB+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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