SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f93a903d06b380bdfefa6347d79bd88c17a63e5bd79de54239398dfbca6be74' 
  AND token = 'CdaWHFX6j6DML/4BZVCagGeKnwZX404pI5fS3nbhybg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}