SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e9bbbb4da42cfc995ebcff00fe2c27a442feec667dc40755bfa3c4016884578' 
  AND token = 'SOw+vNQR5VndvptVWXh+PTQe2Z6rOKvUE252pJGGyKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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