SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '659962be4628763e8d6e38716381e60a82e02775575062706aef53367d36f39b' 
  AND token = '6JqJYWC7YZ2oko/wfIdI+p4y0L37SCCW2eCdiVrq2DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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