SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e79daf2a05e25c6bfc47ba5ec141a59677dade87127ff60886c85af9657f4a' 
  AND token = 'Hm5AL34HjAHv4pBopzDDg6ricBKah2BWz24XOD9szYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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