SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf479b046cd0d8d255da6394d95a7a0c9478bc42ebfce3f0e0d784bd9f2cdf6' 
  AND token = 'ejDKfqy+bmz9qxVQqV2edWyjFQRIlt0/aKspec1i6yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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