SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97f5169acc500142ffb030a6f3b6906a8a99cc0c0fadb59819a0decf3958c644' 
  AND token = 'VnAHGZQuXNkGwQyi2tiM2UP3UYCbHfFN1NwonMR+9so=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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