SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '804bfd593ed704bc90e85e2c50668ab20f723bcadc91f50545377b1c50844ac1' 
  AND token = '/tKauFeA5HlIhIx74831m/HUhDG+wnWZ1k0EMI04Gtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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