SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1927ca29e483f2aae4937611f38d4b4fee69144f619798ff4e88d9cce74d5272' 
  AND token = 'FamKfZgcIaqsS2Vk8SWKusf3sGLZAgng9Bp1Os53/TQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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