SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446a19276da3919310bae589a2e654125e485ca0c9b000f1ceedf0b7431d72e4' 
  AND token = 'LImLOcAG5EstaIeZcw1pNFpIxny21Zg6Liom5g9dvAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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