SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a72e2e82114adff462931e0536cb41352571e872bbc89f11751be52912e83df3' 
  AND token = '8QC/8LjmwRPBRt6DoEkNaQE4iipqLQ1za7cTmJu0xIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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