SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30048c82482341fa06782e004e8841aa834ced00c8dd288ff1e4cce755b94855' 
  AND token = 'YKw4iKkkUVwzBw1KuMUQ6c86CyMCAuCh/8wy+CvvKus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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