SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '968fb450f4649916dcc93fc10359895204c4b53af914c2b6179c35a544e62980' 
  AND token = 'iBkJzfU+622Kb/+2Eu+hWITNI+AWZb6sJOdYDN+wBM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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