SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16e62e423b0abcc8ee11df71da4efa50c691bc8bca3445bca4148e9737181e35' 
  AND token = 'huwmAElmZXKBDeYPg2zhOQFR2CmSbJqDFvOd3jN8Blo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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