SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f761c0280d182a2c3bd8fcf49deb214106a0d28339a8b533852b185c442419b2' 
  AND token = 'lgw4Msl7whYJFvlTNXS6JxXMzxDnE8/RMqzY3FYRzp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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