SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '653b254888ebff149e733660a4ff977b4cc3ac6c975e264ad1ad93dda718dba2' 
  AND token = '+vzmVEeg4LsKz1jJNCxKKlPRL+7RZqfEuNoS6JMjejA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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