SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3026e5daa7a08b3774fd13512b9654ac6e046546f3e7449c9bfbebc30977a93b' 
  AND token = '940tT89zEnnFcL+WRMJ7CBZVUOqV5XuPRhGB1j1ifTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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