SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73d49afc8c5543f13cf4835810c2b804840480105f86f6e3ef9f4a6dac431e4f' 
  AND token = 'OVIhdvyDOvIfa3R6GIBPLDup/hsQEOze9/UyJhno4Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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