SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ef038b8109acbead2577de2a85df337a5ad35271562ad10ccaafa10a6791d9' 
  AND token = 'B7i3jyIpV9aLe+m8xylW37SsgSUsvEzchx34M2oTY64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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