SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '197ea1324203ca20c5a95961c177b6c399b8d73490779febb2b44e8d30847e34' 
  AND token = '6RoNW53q4n8One9eeGrvruHzrlssWWSQtlMcPKvdtUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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