SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69215e33d0ade5bfc12273ea619a0fafa8c35206dc1d62fe75495881c2a86f4d' 
  AND token = '/n1XY8/u2AV+LMgwMmqNMmWYdEXJisUtbQJcnh/uvII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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