SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65acfd2b69554233fa516ff11c52b2f04f4435bf832838e281969cb21fcc1fdb' 
  AND token = '127VWrfcoB4oS4POr6cktwlSSPE9JRtuTsRLDw7BY1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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