SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0538a9327d5410211441257d23642244ee637ff6af74c7dca5006be5cadb3628' 
  AND token = 'waptdGCShxJ2++7M5byTZqq5LyWYHfEuvZpLR3SQKwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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