SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2990b4de18076ce8eb4e9c4fdc574e157884e9e8fff3d6a8981f6dfeff0a6620' 
  AND token = 'oq9G6MeBMXPQlALqNVtNrGra3rML8mZESLh1xiSLTww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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