SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2605a75fefaca56e5ff1a069deb46944817eed80cfe0178774b84666a0713d4e' 
  AND token = 'QUdsH06cAGC2TuxySOHB37CsQsQLOUD53kJpGcn02wY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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