SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc5388fa3740e7956c4630abcde6486f8eaa2fb4c87949c825980cc3b918316a' 
  AND token = 'iLhV+F5+KT8Q2lsWf/3EoiJBD/retV7TkVjgxYqFLq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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