SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ded9687e092152bd1feb1f75caaccc1317463b2996be3b018c23790e6f8eb35' 
  AND token = 'ywTLVtnIN2EYkU90/Cr0O7npo/fqpYqxJywBzgQPuZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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