SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b0d7f2dfb4af35faeccc4f9424357300b166d9f23e2a80bd59f42f8a1c29678' 
  AND token = 'KIhVYEf1TqiJcuGomjxCIHG9x/PhwKQsYx2rG6DozLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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