SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a538ba6359eae5134a095c3cb8dacd8581e3adfbe4c5e93d638ef6931e06abfe' 
  AND token = '77/rAgmekeOFPoLFxebFfzVyS+o5lvK8TUX/9ejqWRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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