SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '583ea0f9c1c25b72708a04157f0a5663d9f5753b5c3e619566b2aa8e260969dd' 
  AND token = 'w6ZpIDgjU3Kq+qzx7JceYaNWtPEHTBXgTdnb7O1wC98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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