SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8fb179405692ccb51f065b448627464260eb9adc0b5190e789cad64b023a8ed' 
  AND token = 'sx7I1e23jRyon/TJTrRZ7qQgIBZWJEzy+A9yxCne4Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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