SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad1cf2deac2e658963977ce5163fb864e0fc52e5f0b717c1a8716a88d250634c' 
  AND token = 'rjIOBhKkGt947rRNqvfTfXBRcwDddxFvKDT7Ua2ZhvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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