SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c3e1753103361ff120181c9b6d4e5e589e0ff5abc7d0d94d071a9247f0253b6' 
  AND token = '0YOsz0l+mIjR18AHNgVAm5slX8hRPQBMGgwc3pv4q1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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