SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfb15fc7b2e3b80d9db9959c0643607489fb841588ac98517733b558013a64d1' 
  AND token = 'u2o4TAHJi6F1XG6uU1LiTyqk9QdKjwyl9x/7VBIE6ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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