SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ada76460413f1921ea76261e8bc1c16f724507b61a8744de441330720fa05090' 
  AND token = 'ZC6ORs0JJORkZ8ajo9msYTWyrhd9w5enCHRJul9VlqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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