SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1925c8c02004c2a75a40d2313d23244e7f220fb6bc4b2151b758d6c8167d450' 
  AND token = 'fPRmWvXnCDakVMDEGhW7AKDPgdZ7J9whQwJwSGMOmD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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