SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e95e8d93eb8b601622f8d9537e9a949db572b9a0e4078e0ab81adf3860894816' 
  AND token = 'tnaMmK/YXlmtMJzQIT25v+HK95IkUqxXYMsbHl/jxfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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