SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa483d22d83f86e3f4153c40f323d154a02ef09327dc575ef8646fcc1f556ce' 
  AND token = '3JNOsJLyL6/Ef7YdGAHBnFGwmCHDdMAiFEPIqbVzDv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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