SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6548a32acc869d7b6c592e719378d29bf15eab84d5c243e341250fe0288ebc1c' 
  AND token = 'BRUlQqxdwyQhGYopzqbcrg7POivxBA+/3K7JnQ/i0fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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