SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b7136e6fa57a19e766f5443a90a128aa6feadc2ff14589e12d53fc03c8df4a7' 
  AND token = 'aHKqppZ8KPkwCwPW358pK1TckLCyYlDS3Np2QMXZ8dM=' 
  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"
    }
  }
}