SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '91f31e8ce709a6c5dc6191ecd04f8698ce9d38c2239dcbcb6eeaff5856dbb2a2' 
  AND token = '2BJZYgOxqEjT3z//7vgaBCaOZC0YyFI4fpI7Df93vGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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