SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fca2b6cb72e8f47401d5f6cf540c42fd0b61f83f7005d9f8c2d0075f2661de3' 
  AND token = 'qHEMDwsPdHiI/jhBn1tzuRPhzJenjf2WNugYg/BYhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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