SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956c25c913c96103e0241f196bad37d05f25cde81fccf3c75885c709333e06d0' 
  AND token = 'YTT7zAg3BejC8aRZ+cmJ7XhyB9K0uKR1sUIbtQMdX7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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