SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0c68b3d5d62ca413bf1eb87928d7936fcb5ecd3e1f65befe694fc436b8afab26' 
  AND token = 'vRHgw89IBA/sCUzfBPwB0wOqhVyUckSdsCYVgAhMBjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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