SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394b4c68cb1439c6e3e7f3ffd00d5b3d8e7fddab6713780bc3f23104daca0425' 
  AND token = 'f7YhmDYf5fckAOEyy3LWVbu2OIlYKUpYhQkWYFj/I1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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