SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '703e2b4d7620183fd63206a6ced0957359ef546cc3377ae0501bb7600dc1725d' 
  AND token = 'N2aWh/i77gixfGBIBTiSsLoqSKZA8okVIuYmO/nDIxc=' 
  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"
    }
  }
}