SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c184d4ec881f5220094962e11995f9152306467fc762947a881a2793386f4d56' 
  AND token = 'cilVwvFz0Z5pTC1+skAy2VBQtFhtY/Hrl8Zr40TmJO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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