SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '817a5523053ef37ffdc9e3bf2e56691697165224be76f154f80919aea051dc79' 
  AND token = 'ZpXAKmy0U91etm75saVzAA/hlGbneUhfEqNJXtOXgJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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