SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91348e961e6d3a16ff4fc5bc8660f92e248c15e902016b3529184981a5c16154' 
  AND token = 'pMb7RoifpRzEScj1ReEz+tZECmGSgNLofCJpXRMmGdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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