SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91cfd31c5255548dfe2ba61b95255c3d558ed60da10b5f36eba5a4f77b1022bd' 
  AND token = 'OjnVq9hn5riDFpKwNYeBsjHCRc0JZjXIR3c+ogzY0wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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