SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e002bb03b91c9da33a01fc8ab61aa3b3f6b2082216c46032a75ba60a2399d439' 
  AND token = '0g/VFvDIsbopVXpBFPXrjM0kCe7wHwuDPYEGME6bGcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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