SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf6ef8c6eaa4e91c16e5e712344bc20657171681e1c42ed24cda2953bad59932' 
  AND token = 'adiGFDClNa7JEYWVXMPxwZQ1UWIxYi1XZgPAoB+X8Hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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