SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94f2b1c58a9056614dfcd52cb44de793ebf107f50bdf7c811124f9802cffe947' 
  AND token = 'A6+o8mCiktzFIMqwFsgqATOiRwI6pVCMWJXiLIgGMkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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