SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e98cc79d94b19dd637e4df594edfeabfaf2a8dfd9acd15d36a3f0f149ac23bee' 
  AND token = '7L0Ul9qqUq1xOmpYBQSDWG+jVhZk7sDxoRyguKCq0rU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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