SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9842b2f593723b72134b1e603d2b206ada6ffb6634e79018ddac6c492542fada' 
  AND token = 'vCfLDhSKJuzv3PQ1v5b1Nr2MDNBv7o/7at3DUR2fWCk=' 
  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"
    }
  }
}